Racking mechanism for disconnecting circuit breaker conductors from switch board conductors



March 14, 1967 G. A. WILSON 3,309,473

RACKING MECHANISM FOR-DISCONNECTING CIRCUIT BREAKER CONDUCTORS FROM SWITCH BOARD CONDUCTORS Filed Nov. 24. 1965 4 Sheets-Sheet 1 March 14, 1967 3,309,473 AKER G. A. WILSON RACKING MECHANISM FOR DISCONNECTING CIRCUIT BRE CONDUCTORS FROM SWITCH BOARD CONDUCTORS 4 Sheets-Sheet 2 Filed' Nov.. 24. 1965 MIhIhNI.

7Min/Ww March 14, 1967 G. A. WILSON 3,309,473

RACKING MECHANISM FOR DISCONNECTING CIRCUIT BREAKER CONDUCTORS FROM SWITCH BOARD CONDUCTORS 4 Sheets-Sheet 5 Filed Nov. 24, 1965 March 14, 1967 G. A. w|| soN RACKING MECHANISM FOR DISCONNECTING CIRCUIT BREAKER CONDUCTORS FROM SWITCH BOARD CONDUCTORS Filed NOV. 24. 1965 4 Sheets-'Sheet 4 I N VEN 'I OR. iff/yf Mu/V United States Patent RACKING MECHANISMFOR DISCONNECTING CIRCUIT BREAKER CONDUCTORS rFROM SWITCH BOARD CONDUCTORS George A. Wilson, Media, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Nov. 24, 1965, Ser. No. 509,580 17 Claims. (Cl. 200-50) This invention relates to circuit breakers and more particularly relates to apparatus for electrically connecting and disconnecting the main and secondary conductors of a circuit breaker to their associated external main and secondary conductors while maintaining the circuit breaker and breaker conductors motionless relative to the associated external conductors and the circuit breaker cubicle through which such associated external conductors pass.

In most uses of large circuit breakers, `the breaker is housed within a suitably dimensioned cubicle. For obvious safety reasons the breaker main and secondary conductors extend from the rear of the circuit breaker whereby they may be electrically connected to associated main and secondary external conductors which pass through the-rear wall of the cubicle. To fulfill basic operating, testing, and servicing requirements, it is normally required that the circuit breaker be -able to fulfill three electrical conditions and in addition thereto, the circuit breaker must be capable of being quicklyk and easily withdrawn from its cubicle or housing.

The three electrical conditions correspond to a connected position in which the breaker main and secondary conductors are electrically connected to their respective external main and secondary conductors; a test position in which the breaker main conductors are electrically isolated from their respective external main conductors, while the breaker secondary conductors or selected ones thereof remain electrically connected to their respective external secondary conductors; and the disconnected condition in which both the breaker main and secondary conductors are electrically isolated from their lrespective external main and secondary conductors. As noted above, a iinal requirement for the breaker, although not electrical in nature, is that the breaker may be easily withdrawn from its cubicle.

Present means for establishing the'variou's electrical i y 'circuit breaker conditions and for withdrawing the breaker from its cubicle comprise racking apparatus interconnected between the circuit breaker and `its cubicle for physically moving the circuit breaker and its main and secondary conductors away from their associated external main and secondary conductors whereby the necessary clearance is established between the breaker conductors and external conductors, respectively. Thus in a normal operating connected position the breaker occupies its most rearward position within its cubicle such that the breaker main and secondary conductors are electrically connected to their respective external conductors. Initial operation of the racking mechanism moves the circuit breaker forward within its lcubicle such that the main breaker conductors, but not the secondary breaker conductors, are of suliicient distance from their associated external main conductors so that electrical clearance is established therebetween. The breaker now occupies the test position. Further ope-ration of the racking mechanism again moves the breaker forward in its cubicle such that the breaker secondary conductors are of sufiicient distance from their respective external secondary conductors to establish electrical clearance therebetween. The breaker is now in its fully disconnected position. Further operation of the racking mech- 3,309,473 Patented Mar. 14,V 1967 anisrn propels the breaker out of its cubicle whereby it can be easily serviced or replaced.

The above described prior art system suffers from many disadvantages, which the instant invention effectively eliminates. Specifically, Yfor safety reasons, it is desirable to move the circuit breaker with the cubicle door closed. Assuming the breaker to be in the fully connected position, i.e., in its most rearward position within the cubicle, an operator cannot reach breaker controls such as manual trip, manual close, racking mechanism, etc..unless these controls are mounted on a projection of the circuit breaker which extends through the cubicle door. It becomes apparent that when the circuit breaker is moved or racked toits test or disconnect position, such projection will necessarily move increasingly forward of the original dimensions detined by the cubicle housing. Obviously this situation requires that more overall space be provided for each circuit breaker and necessarily decreases the space available for other breakers or their peripheral equipment.

As a further disadvantage it 'is noted that in many environments it is required that a circuit breaker be permanently positioned to prevent unintended movement. For instance, if the circuit breaker is to be exposed to shock it is oftentimes required that the breaker be bolted in place during operation.

Obviously with the prior art racking mechanisms described above, wherein the circuit breaker must physically move relative to its cubiclein order to achieve the various electrical positions required, the circ-uit breaker cannot be bolted in its operating or connected position.

In contrast to the prior art racking mechanism described above, the instant invention provides apparatus for electrically connecting and disconnecting the circuit breaker main and secondary conductors from their respective external main and secondary conductors in a positively dened sequence including connected, test and disconnected positions while maintaining the circuit breaker and breaker conductors physically motionless relative to the circuit breaker cubicle and the external conductors passing therethrough.

By providing that the circuit breaker remain stationary relative to its cubicle during the entire sequence of the various electrical conditions, it is readily apparent that the control panel projection discussed above will not be extended increasingly forward of the cubicle when the breaker is being switched between its various circuit ICC positions. Consequently the overall space .required for each and every circuit breaker embodying the instant invention will be materially reduced.

It is further apparent that ,by providing that the circuit breaker remain motionless relative to its cubicle even dur'- ing the electrical'connection or disconnection of the main and secondary conductors, it is now possible for the circuit breaker to be rigidly bolted in place to prevent mishap during frequent or extreme shock conditions.

To accomplish the above noted results, the instant invention provides racking apparatus whereby the main and secondary disconnect contacts, which are normally secured to the breaker conductors for movement therewith, may be moved relative to both the breaker conductors and the stationary external conductors which pass through the cubicle housing.

Specifically, in a three pole breaker of the prior art there would normally be provided six main disconnect contacts secured to and movable with the six extending main breaker conductors. Such main disconnect contacts engage their respective external main conductors when the breaker is moved to its rearmost position within the cubicle.

In the instant invention the six main disconnect contacts are enclosed within a main insulation molded carrier which is moved by racking mechanism (to be further described) between a first position in which the disconnect contacts electrically connect the main breaker conductors and their main external conductors, and a second position in which the disconnects are moved toward the front of the breaker whereby the main breaker conductors and respective external conductors will be electrically isolated.

Similarly, whereas in the prior art devices discussed above, the secondary disconnect contacts were secured to and movable with the breakers secondary conductors, in the instant invention such secondary disconnect contacts are supported within and movable with second insulation molding carriers which are movable 'between a first position in which the secondary disconnect contacts electrically connect the breaker secondary and external secondary conductors, Iand a second position in which the secondary disconnect contacts are moved forward with respect to the breaker such that the breaker secondary conductors and their respective external secondary conductors are electrically isolated.

To effect the predetermined sequence which establishes the connected, test and disconnect positions, in that order, the racking mechanism `of the instant invention provides that upon initial rotation, only the main insulation carrier (and the main disconnect contacts carried thereby) will move between its first and second position thereby electrically isolating only the main breaker conductors from their respective main external conductors. Upon further rotation of the racking mechanism, the secondary insulating carriers, and the secondary disconnect contacts carried thereby, are moved -to their second positions whereby a selected number of the secondary disconnect contacts break contact with their respective external secondary conductors and the remaining secondary disconnect contacts remain in contact with as many long external secondary conductors as may be required for electrical operation of the breaker while in the test position. Thus by a predetermined amount of rotation of the racking mechanism the breaker has undergone a change from the fully connected to the test position without moving the lbreaker relative to its cubicle.

Further rotation of the racking mechanism moves the secondary insulating carriers and the secondary disconnects carried thereby to a final position in which all of the secondary disconnect contacts break contact with their respective external secondary contacts. The breaker is now in the fully disconnected position.

As a further feature of the instant invention, further rotation of the racking mechanism to an out position defeats a simple mechanical interlock whereby the circuit breaker may be easily withdrawn from its cubicle.

As another feature of the instant invention there are provided novel positioning means whereby the racking mechanism automatically and positively stops at each of the connected, test and disconnected positions, to call the operators attention to the positions reached.

As a further advantageous feature of the instant invention there is provided interlock mechanism whereby the racking mechanism will be inoperative if the breaker contacts are closed, and whereby the breaker contacts cannot be closed whenever the racking mechanism is being operated or thebreaker is being withdrawn from its cubicle.

It is therefore seen that it is an object of the instant invention to provide apparatus for electrically connecting and disconnecting breaker conductors from their respective external conductors while maintaining the circuit breaker and breaker conductors physically motionless relative to their respective external conductors.

It is a further object of the instant invention to provide apparatus for electrically connecting and disconnecting circuit breaker conductors and their associated external conductors while maintaining the circuit breaker and breaker conductors motionless relative to their respective external conductors, which apparatus comprises conductive disconnect contacts movable relative to the breaker vthe circuit breaker physically motionless relative to the cubicle in which it is housed.

Still ano-ther object of the instant invention is to provide such apparatus wherein means are provided for automatically `and positively locating each of the connected, test and disconnected conditions to call the operators attention to the condition established.

Yet another object of the instant invention is to provide racking mechanism `for establishing a circuit breaker connected, testV and disconnected condition, with such racking mechanism including positioning means cooperatp ing therewith for automatically stopping and preventing further movement thereof when the circuit breaker has exactly achieved one of said connected, test or disconnected positions.

Yet another object of the instant invention is to provide such racking mechanism which includes releasing means for releasing the positioning means to allow further change in the circuit breaker condition.

Yet another object of the instant invention is to provide such racking mechanism which includes interlock means associated with the positioning means for allowing the cooperating contacts of the circuit breaker to assume their engaged or closed position only when the circuit breaker is exactly located in one of its connected, test or disconnected condition.

Still another object of the instant invention is to provide such racking mechanism which includes additional interlock means whereby the circuit breaker may be withdrawn from its associated cubicle only after such racking mechanism has reached a predetermined position.

Other objects of the instant invention will become apparent to those skilled in the art upon reading the following description when taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a somewhat schematic showing of a circuit breaker in which the instant invention may find application;

FIGURE 2 is a partial side view of the instant invention positioned within a circuit breaker of the -type illustrated in FIGURE 1;

FIGURES 2a and 2b are detailed views of a portion of l the racking mechanism shown in FIGURE'Z illustrating the various positions occupied by various parts thereof;

FIGURE 3 is a partial plan view taken along the arrows 3-3 of FIGURE 2;

FIGURE 4 is a perspective view of the instant inven tion illustratively shown on a portion of the circuit breaker illustrated in FIGURE l;

FIGURE 5 is an exploded perspective view of a portion of the racking mechanism shown in FIGURE 4; and

FIGURE 6 is a partial plan View of a mechanical interlocking mechanism which comprises a part of the instant invention.

Referring to FIGURE l, there is shown a circuit breaker 10 housed within a circuit breaker cubicle or housing identified as 12. As is conventional in theart the door 14 of cubicle 12 may be opened to permit the circuit breaker to be withdrawn by means of wheels 16. Breaker 10 includes 3 pairs of rearwardly extending main conductors 18 and 2t) (only one pair being shown) which are to be electrically connected and disconnected by main disconnect contact pairs 22 and 24 (only one pair being shown), carried by a main insulation molded carrier 26, to 3 pairs of external main conductors 28 and 30 (only one pair being shown) which pass through the rear ywall 32 of the cubicle 12.

Similarly, breaker includes multiple pairs of secondary conductors 34 and 36 (only one pair being' shown) which are to beelectrically connected anddisconnected by means of secondary disconnect contacts 38 and 40 (only one pair being shown), carried by secondary insulation moldings 42, to multiple pairs of external secondary conductors 44 and 46 which pass through the rear wall 32 of the cubicle 12. The breaker main and secondary conductors 18, and 34, 36, respectively, are spaced apart and secured in place by an insulating support molding generally indicated at 48.

The opposite end of conductor 18 is electrically connected to a substantially U-shaped stationary contact structure 50 which cooperates with movable contact 52 pivoted to rotate about pivot point 54 on the opposite end of conductor 20. Movable contact 52 is schematically connected by links 56 and 58 to a jack shaft 60. Rotation of jack shaft 60 in response to energization of either a time-delayed tripping device (not shown) calibrated for overload conditions or an instantaneous tripping device (not shown) calibrated for extremely high fault current, rotates movable contact 52 between its engaged and tripped positions.

As is conventional, stationary contact structure 50' and movable contact 52 are each provided with main and auxiliary contacts 62, 64 and 66, 68, respectively, arranged such that main contacts 62 and 66 separate before auxiliary contacts 64 and 68. Thus an arc being drawn between contacts 64 and 68 maybe readily transferred to arc runners 70 and 72 which extend upwardly into an are chute 74v wherein the rising arc may quickly be extinguished.

It is to be understood that although FIGURE 1 shows only one phase, the circuit breaker shown in FIGURE 1 can be a multi-phase breaker wherein each phase is provided with similar apparatus to provide circuit interruption and arc extinguishment therein.

Furthermore, it is to be understood that although the instant invention will be described with respect to a multipole breaker, the concept of the instant invention may be equally applied to a circuit breaker comprising one or more poles.

As will be explained in greater detail, main insulation carrier 26 and the main disconnect Contact pairs 22 and 24 caried thereby are adapted to be moved by racking mechanism, only a portion of which is shown at 76, between a first position shown in FIGURE 1, wherein the main disconnect contacts 22 and 24 electrically connect breaker conductors 18, 20 with external conductors 28, 30 and a second position indicated by the phantom lines 78 wherein the disconnect contacts 22 and 24 break contactwith the conductors 28, 30 to establish electrical isolation between the conductors 18, 28 and 20, 30.

Similarly, by means o-ffthe racking mechanism noted above, another portion of which is indicated at 80, the secondary insulation carriers 42 and the secondary disconnect contacts 38 and 40 carried thereby are movable between a first position, shown in FIGURE 1, to an intermediate position, illustratively shown by the phantom lines 82, wherein some of the secondary disconnect contacts will have broken contact with their respective external secondary contacts and others of the secondary disconnect contacts will remain engaged with longer ex- Y ternal secondary contacts 84, which may be required to operate the circuit breaker in the test position. Secondary insulation carriers 42 are further movable to a nal posi# tion (shown by phantom lines 85) in which all of the secondary disconnect contacts carried thereby are disconnected from their respective external secondary conductors. As will be described in greater detail, the movea predetermined sequence vwhich allows an operatorto establish the various connected, test, disconnected, and out conditions required for the circuit breaker.

nient of the main and secondary insulation carriers is in i As clearly seen in FIGURE 2, main insulation carrier 26 comprises two back-to-back insulating shells 86 and 88 which are joined together as at 90 to form a plurality of pockets 92 for the reception of the main disconnect contacts 22 and 24. It will be appreciated that .for a three-pole breaker six such pockets 92 will be required, but it is to be understood that the shells 86 and 88 may bepreformed to establish any number of such pockets as may be necessary in a breaker having more or less than three poles.

The disconnect contacts 22, 24 are conventional in nature and are seen to comprise a main conducting portion 94 and a plurality of garter springs 96 to urge the end portions of main conducting portion 94 into firm electrical contact with the conductors 18 and 28. FIG- URE 3 represents a plan View of the insulation carrier 26 and shows the six pockets 92 which would be necessary for the three-pole breaker.

Secondary insulation carriers 42 are seen to comprise insulation channels Within which are lodged the secondary disconnect contacts 38 and 40. Garter springs 98 surround secondary disconnects 38 and 40 `and urge the ends thereof into rm electrical contact with the breaker secondary conductors 34, 36 and the external secondary conductors 44 and 46.

As shown in FIGURE 2 and as will be described in further detail, main insulation carrier 26 is rigidly secured by a suitable fastening means to a pair of substantially rectangular blocks. 102 (see FIGURES 4 and 5) which pass through insulation molding 26 at positions substantially one-third along the length thereof and midway of its height (see FIGURE 3). Each block 102 is secured between a pair of rigid bars 104 and 106 by suitable fastening means (see FIGURES 4 and 5). Bars 104 and 106 are otherwise joined along their lengths by pin 108 located intermediate their ends and pin 110 located at the end opposite block 102. It is noted that rigid bars 104 and 106 pass through and are movable within a passageway 112 provided by the cooperation of a pair of recessed notches provided in any two adjacent lead support moldings 48. As will be further described, rigid connecting bars 104, 106 and main insulation carrier 26 are all movable in response to rotation of a cam plate 114, which etfects engagement of one notch 116 thereof, and the pin 110.

The secondary insulation carriers 42 are secured by suitable fastening means to one end of a depending member 118 the opposite end of which is rigidly secured by suitable fastening means between a second pair of rigid connecting bars 120 and 122 which reside between the rigid bars 104, 106 in the manner shown in FIGURE 5.

The opposite end of rigid bars 120 and 122 are joinedbya pin 124v and are further provided with an extension 126 which rests on pin 110 so as to permit relative motion therebetween. The opposite end of bars 120, 122 are each provided with elongated slots 128 by means of which the rigid bars 120 and 122 may be further supported on pin 108 for slidable motion relative to bars 104 and 106. As will be explained in greater detail, rigid connecting bars 120, 122, depending member 118, and secondary insulation carriers 42 are movable in response to continued rotation of cam plate 114 which effects engagement of a second spaced apart notch 130 thereof and the pin 124 joining bars 120 and 122.

As indicated in FIGURES 2 and 4, are rotatable about the jack shaft 60 and comprise a generally circular plate having the pair of spaced apart notches 116 and 130 along their peripheral surface. To assure secure engagement between these notches and the pins 110 and 124, the notches 116 and 130 are provided with extending surfaces 132 Land 134, respectively, on opposite sides thereof.

The establishment of the various circuit breaker electrical conditions will now be explained with reference to FIGURES 2, 2a and 2b, it being noted that the following description will be limited to one cam plate 114 only.

cam plates 114 It is to be understood that the second cam plate 114 experiences identical movement. Referring initially to FIGURE 2 it may be seen that the circuit breaker is in the fully connected position. That is, the main disconnect contacts 22 and 24 electrically connect breaker conductors 18, 28 and 20, 30, respectively. Also, secondary disconnect contacts 38 and 40 electrically connect breaker secondary conductors 34, 36 with external secondary conductors 44, 46, respectively. Upon initial rotation of cam plate 114, pin 110 is engaged by notch 116 of cam plate 114 to move the pin 116, the rigid bars 104, 106, the rectangular block 102, and main insulation carrier 26 to the right.

The pin 124, which is joined to the secondary insulation carriers 42 through rigid bar members 128, 122 and depending member 118, is not moved until the notch 130 in cam plate 114 has rotated suiciently counterclockwise (in FIGURE 2) to engage pin 124. After a predetermined amount of rotation, the exact amount of which will be determined by novel positioning means to be described in greater detail, cam plate 114 reaches the position shown in FIGURE 2a wherein the pin 110 has moved from its initial position to a position indicated as 110 and the pin 124 has moved to a position indicated by 124.

The above described movement lof pins 110 and 124 accomplishes two results, namely, (l) the main insulation carrier 26 and the main disconnect contacts 22 and 24 carried thereby have been moved toward the front door 14 of the circuit breaker cubicle by a sucient amount to break contact with the main external conductors 28, 30, and (2) the secondary insulating carriers 42 and secondary disconnect contacts 38 and 40 have been moved to the right by only one-half of their total travel. This intermediate position of the secondary disconnect contacts permits some of those contacts to break contact with their respective external secondary conductors and permits others to remain in contact with as many long external secondary conductors 84 (FIGURE 2) as may be required for electrical operation of the breaker while in the test position. As noted, the position of the cam plate 114 shown in FIGURE 2a corresponds to the circuit breaker test condition.

To change the circuit breaker from the test position to the fully disconnected position, the cam plate 114 is rotated once again, until the pin 124' shown in FIG- URE 2a has moved to the right to occupy the position 124 shown in FIGURE 2b. This causes the secondary disconnect contacts 38, 40 to be retracted their full travel to lbreak all electrical circuits. It is noted that during rotation of the cam plate 114 from the position in FIGURE 2a to the position in FIGURE 2b, the pin 110 experiences no further movement since the notch 116 has long since disengaged from that pin 110.

With reference to FIGURES 2 and 4 there is shown the mechanism for effecting the rotation and positioning of the cam plate 114. Suitably secured to the circuit breaker are a pair of L-shaped brackets 134 having apertures which support a freely rotatable hexagon shaft 136. Secured to each end of the shaft 136 for rotation therewith is a circular crank arm 138 having a plurality of positioning notches 140, 142 and 144 along their peripheral surfaces (see FIGURE 2). Crank arms 138 further include a V-shaped notch 146, the purpose of which will be explained in greater detail. Each crank arm 138 further includes a pair of outstanding pins 148, 150 which extend in opposite directions from their respective crank arms. Pin 148 is a stop pin and limits the rotation of crank arms 138 to an arc defined by the initial position of stop pin 148 and a ledge 152 defined by L-shaped bracket 134. Pins 150 which extend in an opposite direction from pins 148 are pivot pins about which one end of the double pronged links 154 may rotate. The opposite end of the links 154 are connected to cam plates 114 by suitable pivot pins 156. Mounted centrally on shaft 136 for rotation therewith is a cylindrical disc 158 having a plurality of holes on its exterior surface. It will be apparent that rotation of crank arms 138 caused by rotation of cylindrical disc 158 (as by a handle inserted in one of the holes 160) will effect rotation of cam plates 114 through the links 154.

To automatically and positively stop the rotation of cam Iplates 114 and hence stop the motion of the main and secondary insulation carriers at each of the various positions, there is provided a lever 162 arranged to rotate upon jack shaft 60. Lever 162 is seen to include three outstanding arms 164, 166 and 168. Arm 168 includes a locking projection 170 which is urgedinto.

one of the position identifying notches 140, 142 or 144 under the bias of a spring 172 secured between the arm 164 of lever 162 `and a portion 174 of the circuit breaker. It Will be apparent that with the locking projection 170 inserted within one of the notches 140, 142, 144, further rotation of the cylindrical disc 158 becomes impossible.

Assuming that the breaker is now in the fully connected position shown in FIGURE 2 and is to be changed to the testposition, the operator first rotates lever 162 counterclockwise (by means of arm 166) against the bias of spring 172 to lift the locking projection 170 out of the position receiving notch 144 which, in effect, exactly locates the fully connected position. It is noted that the lever 162 may only be rotated if a blocking pin shown at 176 in FIGURE 2 has been moved out of th`e path of a small projection 178 extending from the lever 162. For safety reasons the pin176 is only moved out of the path of projection 178 when the movable contact 52 has become disengaged from the stationary contact 50 shown in FIGURE l. Thus the mechanism of the instant invention may only be operated when the circuit breaker contacts are open.

As a further safety feature it is noted that when arm 166 of the lever 162 is rotated counterclockwise to withdraw the locking projection 170 from one of the positionidentifying notches, the lower arm 164 occupies a position indicated in phantom lines at 164 whereby the trip latch 180 of the circuit breaker is held in a down position. Thus when the circuit breaker is being changed between the various connected, test, and disconnected conditions, the cooperating -contacts 50 and 52 of the breaker may not be closed.

Assuming the locking projection 170 has been moved to the position indicated at 170' in FIGURE 2, the cylindrical disc 158 and thus crank arms 138 are rotated clockwise with respect to FIGURE 2 until the positionidentifying notch 142 is Ialigned with projection 170. At this point the bias of spring 172 rotates lever 162 clockwise to insert locking projection 170 into position-identifying notch 142. The spacing provided between notches 142 and 144 on crank arms 138 corresponds to the exact distance necessary to establish the test condition of the main and secondary disconnect contacts. Since arm 164 of lever 162 is rotated back to the solid line position shown in FIGURE 2 it is apparent that the trip latch 180 may be operated and the circuit breaker contacts 50 and 52 may be closed. However, it is noted that further rotation of lever 162 will be prevented by pin 176 until the contacts 50 and 52 have become disengaged.

To establish the disconnect condition, the lever 162 is rotated once more to unlock the mechanism, and the crank arms 138 and cam plates 114 are again rotated. Rotation is continued until position-identifying notch 140 of crank arm 138 is aligned with locking projection 170 whereupon the bias of spring 172 urges projection 170 into such notch. The distance between position-identifying notches 140 and 142 corresponds exactly to the distance by which the pin 124 must be moved in order to fully disconnect the secondary disconnect contacts from the long external secondary conductor 84, and thus the circuit breaker is automatically and positively established in the disconnect position.

Assuming that it is desirable to Withdraw the circuit breaker from its cubicle the lever 162 is rotated once more to disengage the projection 170 from the notch 140. Rotation of the cylindrical disc 158 is continued as before but in this case no further notch has been provided to receive the locking projection 170. Thus it is apparent that when the circuit breaker is being withdrawn from the cubicle, arm 164 will occupy the position 164 at all times and thus prevent closing of the circuit breaker contacts. Rotation of the cylindrical disc 158 is continued until the stop pins 148 extending inwardly from crank arms 138 engage the ledges L-shaped brackets 134. At this time the V-shaped notch 156 positions itself such that one corner of a rectangular member 180 may pass freely therethrough. This corresponds to the out position.

The rectangular member 180 is secured to a handle 182 pivoted on the circuit breaker at 184 (see FIGURE 6) such that if the handle is moved toward the center of the circuit breaker a locking portion 186 thereof clears itself of an inwardly turned corner 188 of the circuit breaker cubicle. It is to be understood that a similar locking device is provided on the opposite side of the circuit breaker, which locking device may only be defeated when the V-shaped notch 146 of crank arm 138 is appropriately positioned with respect to another rectangular member 180. With the interlocks provided by handles 182 defeated, the breaker may be completely withdrawn from the circuit breaker.

Reinsertion 4of the circuit breaker into the cubicle and the changing of circuit breaker conditions from fully disconnected to test to fully connected conditions are identical to that described above but are performed in the reverse manner.

Thus there has been described apparatus for accurately and positively establishing and changing a circuit breaker between its various connected, test, disconnected, and out positions while maintaining the circuit'breaker motionless relative to the cubicle in which it is housed. Y

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited not by the specific disclosure herein, but only by the appending claims.

What is claimed is: 'f

1. In a circuit breaker having a breaker conductor adapted to be electrically connected to an associated external conductor, the improvement comprising means for electrically connecting and' disconnecting said breaker 152 provided on conductor and its associated external conductor whilemaintaining said circuit breaker and breakerfconductor motionless relative to said external conductor, said means comprising:

a conductive disconnect contact movable relative to said ,breaker conductor and said external conductor bey tween a rst position in which said disconnect contact electrically connects said breaker conductor and said external conductor, and a second position in which said breaker conductor and said external conductor are electrically isolated; and racking means secured to said circuit breaker and said disconnect contact for selectively moving said disconnect ycontact between its first* and second position; and

positioning means cooperating with said racking means for automatically stopping and preventing further movement of said disconnect contact when it has reached the exact location of its first or second position.

2. The means of 'claim 1, wherein said positioning means includes releasing means for releasing said positioning means to allow further movement of said disconnect contact. Y

3. In a circuit breaker having a pair of cooperating contacts operable between an engaged and, disengaged position and a pair of breaker conductors each electrically connected at one end to one of said cooperating contacts and each adapted at the other end to be electrically connected to an associated external conductor which passes through one wall of a circuit breaker cubicle in which said circuit breaker is housed; the improvement comprising means for electrically connecting and disconnecting said other end of said breaker conductors to their associated external conductors while maintaining said circuit breaker and breaker conductors motionless relative to said circuit breaker cubicle and said associated external conductors, said means comprising:

a pair of conductive disconnect contacts movable relative to said breaker conductors, their associated external conductors, and said cubicle, between a rst position in which said disconnect contacts electrically connect each of said other ends of said breaker conductors with its associated external conductor and .a second position in which each of said other ends of said breaker conductors and its associated external conductor are electrically isolated;

racking means secured to said circuit breaker and said disconnect contacts for selectively moving said disconnect contacts between their rst and second positions;

positioning means cooperating with said racking means .for automatically stopping and preventing further movement of said disconnect contacts when they have reached the exact location of their first and second positions, said positioning means including releasing means for releasing said positioning means to allow t further movement of said disconnect contacts; and

interlock means associated with said positioning means for allowing said cooperating contacts to assume their engaged position only when said disconnect contacts are exactly located in their iirst or second positions.

4. In a circuit breaker having a main breaker conductor and a secondary breaker conductor adapted to be electrically connected and disconnected in a predetermined sequence with an external main conductor and a secondary conductor, respectively, which pass through one wall of a cubicle in which said breaker is housed, the improvement comprising means for electrically connecting and disconnecting said main and secondary breaker conductors with theirv associated main and secondary external conductors in said predetermined sequence while maintaining said circuit breaker and said main and secondary ibreaker conductors motionless relative to their associated external conductors and said cubicle, said means comprising: v

a main conductive disconnect contact movable relative to said main breaker conductor and its associated main external conductor between a rst position in which said Vmain disconnect contact electrically connects said main breaker conductor and said main external conductor, and a secon-d position in which said main breaker conductor and its `associated main external conductor are electrically isolated;

a secondary conductive disconnect contact movable relative to said secondary breaker conductor and yits Vassociated -secondary external conductor between a first position in which said secondary conductive disconnect contact electrically connects said secondary breaker conductor with its associated secondary external conductor, and a second position in which -said secondary Ibreaker conductor is electrically isolated from its associated secondary external conductor; and

.racking ymeans secured to said circuit breaker and said main and secondary disconnect contacts for selectively moving said main disconnect contact between its first and second position, and for moving said secondary disconnect contact between its first and second positions at a predetermined time interval after the movement of said main disconnect contact between its irst and second position.

5. The means of claim 4, and further including positioning means cooperating with said racking means for automatically stopping and preventing further movement of saidmain and secondary disconnect contacts when they have reached the exact location of their tirst and second positions, respectively.

6. The means of claim 5, wherein said positioning means includes releasing means for releasing said positioning means to allow further movement of said main and secondary disconnect contacts.

7. In a circuit breaker having a pair of cooper-ating contacts operable between an engaged and disengaged position, a pair of spaced apart main breaker conductors each electrically connected at one end to one of rsaid cooperating contacts and each adapted at the other end to lbe electrically connected to an associated external main conductor, and a plurality of secondary lbreaker conductors adapted to `be electrically connected to respectlve ones of a plurality of external secondary conductors, the improvement comprising means for electrically connecting and disconnecting said main and secondary breaker conductors from their associated main and secondary external conductors in a predetermined sequence while maintaining said circuit breaker and main and secondary conductors iixed relative `to their associated main and secondary external conductors, respectively, said means comprising:

a pair of main conductive disconnect contacts movable relative to said main breaker conductors and their respective main external conductors between a lirst position in which said main disconnect contacts electrically connect each of said other ends of said main breaker conductors with its respective main external conductor, and a `second position in which each of said other ends of said main breaker conductors and its respective main external conductor are electrically isolated;

main insulating carrier means supporting said main disconnect contacts in spaced relation with respect to said main breaker conductors, movement of said main insulation carrier means causing corresponding movement of said main disconnect contacts;

a plurality of secondary conductive disconnect contacts movable relative to said secondary breaker conductors and their respective secondary external conductors between a first position in which said plurality of secondary disconnect contacts electrically connect said secondary breaker conductors wit-h their respective secondary external conductors and a second position in which said secondary lbreaker conductors are electrically isolated from their respective secondary external conductors;

secondary insulating carrier means supporting said secondary disconnect contacts in spaced relation about said secondary breaker conductors; and

racking means secured to said circuit breaker and said main and secondary insulating carrier means for selectively moving said main disconnect contacts -between their first and second positions and for moving said secondary disconnect 'contacts between their first and second positions at a predetermined time interval after the movementof said main disconnect contacts between their first and second positions.

8. The means of claim 7, wherein said racking means comprises:

cam means rotatably mounted on said circuit breaker;

first connecting means operatively connected to said cam means and said main insulating carrier means for movement of said main insulating carrier means in response to rotation of said cam means; and

second connecting means operatively connected to said cam means and said secondary insulating carrier means for movement of said `secondary insulating carrier means in response to rotation of said cam means beyond a predetermined amount.

9. The apparatus of claim 8, wherein:

said cam means includes a pair of spaced apart notches on its peripheral surface;

said rst connecting means comprises a lirst pair of spaced apart rigid members secured to said main insulating carrier means at one end thereof and joined by a first pin at their other ends thereof;

|and said second connecting means comprises a second pair of rigid members spaced Within, and movable relative to, said first pair of rigid members, said second pair of rigid members being secured to said secondary insulating carrier means at one end thereof and being joined by a second pin at their other ends thereof;

said first pin being engaged and moved by one of said pair of spaced apart notches in response to a first amount of rotation of said cam means;

said second pin being engaged and moved by the second one of said pair of spaced apart notches in response to rotation of said cam means a predetermined amount beyond said iirst amount.

10. The means of claim 8, and further including:

crank means rotatably mounted on said circuit breaker and linked to said cam means, rotation of said crank means causing rotation of said cam means, said crank means having a plurality of position locating notches therein, said notches corresponding to the locations of said iirst and second positions of said main and secondary disconnect contacts; and

lever means rotatably mounted on said circuit breaker, said lever means including a locking projection biased against said crank means, said locking projection falling into said position locating notches and preventing further rotation of said crank means when said main and secondary disconnect contacts reach their iirst and second positions.

11. The means of claim 1U, wherein said lever means may be rotated to remove said locking projection from said position locating notches -to allow further rotation of said crank means, and said lever means includes interlock means for preventing said cooperating contacts from assuming their engaged position when said locking projection is out of said position locating notches.

12. The means of claim 11, wherein said main and secondary external conductors pass through the rear wall of a circuit breaker cubicle in which said circuit breaker is housed; said crank means is provided with an additional notch thereon; and said circuit Ibreaker is provided with interlock means which cooperate with said circuit breaker cubicle to prevent withdrawal of said circuit breaker from said cubicle when said locking projection of said lever means is located in one of said position locating notches; said interlock means includes interlock defeater means which enters said additional notch to defeat said interlock means after a predetermined amount of rotation of said crank means.

13. In combination:

a circuit breaker cubicle having an external conductor passing through one wall thereof;

a circuit breaker removably secured within said cubicle, said circuit breaker having a breaker conductor adapted to be electrically connected to said external conductor;

and means for electrically connecting and disconnecting said breaker conductor from said external conductor while maintaining said circuit breaker and breaker conductor motionless relative to said cubicle and external conductor, said means including;

a conductive disconnect contact movable relative to said `breaker conductor and said external conductor lbetween a Ist position in which said disconnect contact electrically connects said breaker conductor and said @Xtefnal Conductor, `and a second position in which said breaker conductor and said external conductor are electrically isolated; and

racking means secured to said circuit breaker and said disconnect contact for selectively moving said disconnect contact between its rst and second position.

14. The combination of claim 13, and further including positioning means cooperating with said racking means for automatically stopping and preventing further movement of said disconnect contact when it has reached the exact location of its rst or second position, said positioning means including releasing means for releasing said positioning means to allow further movement of said disconnect contact.

15. In combination:

a circuit breaker cubicle having a pair of main external conductors and a pair `of secondary external conductors passing through one wall thereof;

a circuit breaker xedly secured within said cubicle, said circuit breaker having a pair of main breaker conductors and a pair of secondary breaker conductors adapted to be electrically connected to said main and secondary external conductors, respectively;

and means for electrically connecting and disconnecting said main and secondary breaker conductors from said main and secondary external conductors, respectively, in a predetermined sequence while maintaining said circuit breaker motionless relative to said cubicle, said means including;

a pair of main conductive disconnect contacts movable relative to said main lbreaker conductors and their respective main external conductors between a first position in which said main disconnect contacts electrically connect said main breaker conductors with their respective main external conductors, and a second position in which said main breaker conductors are electrically isolated from their respective main external conductors;

a pair of secondary conductive disconnect contacts movable relative to said secondary breaker conductors and their respective secondary external conductors between a rst position in Which said pair of secondary disconnect contacts electrically connect said secondary breaker conductors with their respective secondary external conductors, an intermediate position in which at least one of said secondary breaker conductors is electrically isolated from its respective secondary external conductor, and a second position in which both of said secondary breaker conductors are electrically isolated from their respective secondary external conductors; and

racking means secured to said circuit breaker and said main and secondary disconnect contacts for selectively moving said main disconnect contacts between their rst and second positions and for moving said secondary disconnect contacts between their rst, intermediate, and second positions ata predetermined time interval relative to the movement of said main disconnect contacts between their first and second positions.

16. The combination of claim 15, wherein:

said main and secondary disconnect contacts are supported and maintained in spaced relationship with respect to said main and secondary breaker conductors, respectively, by main and secondary insulating carrier means, respectively, said carrier means being movable relative to said main and secondary breaker conductors; and

said racking means includes:

cam means rotatably mounted on said circuit breaker;

first connecting means operatively connected to said cam means and said main insulating carrier means for movement of said main isulating carrier means in response to rotation of said cam means; and

second connecting means operatively connected to said cam means and said secondary insulating carrier means for movement of said secondary insulating carrier means in response to rotation of said cam -means beyond a predetermined amount.

17. The combination of claim 16, and further including:

crank means rotatably mounted on said circuit breaker and linked to said cam means, rotation of said crank means causing rotation of said cam means, said crank means having a plurality of position locating notches therein, said notches corresponding to the locations of said first and second positions of said main and secondary disconnect contacts; and

lever means rotatably mounted on said circuit breaker, said lever means including a locking projection biased against said crank means, said locking projection falling into said position locating notches and preventing further rotation of said crank means when said main and secondary disconnect contacts reach their first and second positions.

References Cited by the Examiner UNITED STATES PATENTS lli/1961 Bodenschatz et al 20G-50 ROBERT K. SCHAEFER, Primary Examiner, 

1. IN A CIRCUIT BREAKER HAVING A BREAKER CONDUCTOR ADAPTED TO BE ELECTRICALLY CONNECTED TO AN ASSOCIATED EXTERNAL CONDUCTOR, THE IMPROVEMENT COMPRISING MEANS FOR ELECTRICALLY CONNECTING AND DISCONNECTING SAID BREAKER CONDUCTOR AND ITS ASSOCIATED EXTERNAL CONDUCTOR WHILE MAINTAINING SAID CIRCUIT BREAKER AND BREAKER CONDUCTOR MOTIONLESS RELATIVE TO SAID EXTERNAL CONDUCTOR, SAID MEANS COMPRISING: A CONDUCTIVE DISCONNECT CONTACT MOVABLE RELATIVE TO SAID BREAKER CONDUCTOR AND SAID EXTERNAL CONDUCTOR BETWEEN A FIRST POSITION IN WHICH SAID DISCONNECT CONTACT ELECTRICALLY CONNECTS SAID BREAKER CONDUCTOR AND SAID EXTERNAL CONDUCTOR, AND A SECOND POSITION IN WHICH SAID BREAKER CONDUCTOR AND SAID EXTERNAL CONDUCTOR ARE ELECTRICALLY ISOLATED; AND 